Order of mutational acquisition in T-ALL development. (A) Kaplan-Meier plot of mice that received transplantation with control, Dnmt3a^HET-, and Dnmt3a^KO-NICD–expressing cells and injected with pIpC 5 weeks after transplant. (B) Schematic for generation of 2-hit Dnmt3a loss-of-function NICD gain-of-function genetic mouse models. (C) Western blot showing expression levels of NICD from doxycycline-induced RTN mice with comparison with levels resulting from retroviral NICD expression. (D) Kaplan-Meier plot showing time to morbidity of RTN and RTN3a mice injected with pIpC and secondarily induced for NICD expression with doxycycline chow. (E) Kaplan-Meier plot showing time to morbidity of RTN and RTN3a mice induced for NICD expression with doxycycline chow then secondarily injected with pIpC. (F) Summary of in vivo DNMT3A CRISPR experiments with wild-type DNMT3A T-ALL specimens showing secondary transplant blood engraftment (6-8 weeks after transplant), time to morbidity, final disease burden at euthanasia, and protein levels of DNMT3A in T-ALL blasts at euthanasia.